Mike Jensen, director of the FBI's Intermountain West digital forensics lab, demonstrates how data can be extracted from any cellphone on July 18, 2011, in Salt Lake City. (Photo: AP/Lynn DeBruin)

For months, the cellphones of a Charles County coach charged with sexually assaulting boys sat waiting. For months, no one saw the videos or images that depict the abuse at his home and in a classroom. And for months the former teaching assistant was free.

Investigators don’t know whether any more children might have fallen prey between the time the phones were seized in December and Carlos Bell’s arrest on June 30 for assault and child pornography charges.

But due to a backlog of work at a Maryland State Police computer forensic lab, the monthslong wait is not unusual, officials said.

“It takes 8 months on any case when you’re talking about computers. You have, in a new day and age, computers and other devices are used all the time in crime, and we have not upgraded the forensics unit as far as personnel and resources,” said Charles County State’s Attorney Anthony Covington.